Pulmonology Section, Department of Pediatrics, University of Arkansas for Medical Sciences/COM and Pediatric Aerosol Research Laboratory at ACHRI, Little Rock, Arkansas 72202, USA.
J Aerosol Med Pulm Drug Deliv. 2010 Dec;23(6):397-404. doi: 10.1089/jamp.2010.0834. Epub 2010 Oct 19.
Cooling the Next Generation Impactor (NGI) is recommended to minimize evaporation due to heat transfer from impactor to aerosols when evaluating nebulized solutions. This methodology increases testing time for serial testing procedures. We hypothesize that after an initial prolonged cooling time, experiments could be repeated after shorter recooling times without sacrificing accuracy.
Three units of continuous output (HUDSON) and breath enhanced (PARI LC Plus) nebulizers were operated (6 L/min) with albuterol solution (2.5 mg/3 mL) into a cooled (4°C) NGI (internal and external filters) calibrated at 15 L/min. Mass median aerodynamic diameter (MMAD), geometric standard deviation (GSD), % particles <5 μm (P%<5), and % particles 1-3 μm (P%1-3) were compared with three different protocols. Initial cooling of the NGI (90 min for all protocols) was followed by two measurements with recooling intervals of either 90 and 90 (protocol A), 60 and 60 (protocol B), or 30 and 30 min (protocol C). Albuterol was diluted and measured by spectrophotometry (276 nm).
MMAD, GSD, P%<5, and P%1-3 for first measurements of all protocols (n = 9) were: 3.47 ± 0.21 μm, 2.31 ± 0.07, 67.3 ± 2.6%, and 40 ± 2.3% (PARI) and 4.56 ± 0.35 μm, 2.16 ± 0.08, 54 ± 3.7%, and 22.4 ± 2.8% (HUDSON). No differences were found between cooling protocols (p > 0.05). Percentage of variation from first measurement ranged from: -3.9 to +2.1% (PARI) and -4.1 to +2.9% (HUDSON) for MMAD; -5.6 to +2.6% (PARI) and -4.9 to +1.9% (HUDSON) for GSD; 0 to +4.6% (PARI) and -3.7% to +5.7% (HUDSON) for P%<5; and -2.4 to +5.2% (PARI) and -1.8 to +4.9% (HUDSON) for P%1-3.
Aerosol characteristics of nebulized solutions determined by NGI are not affected by performing two repeat measurements after recooling the impactor for either 30 or 60 min after an initial 90-min time.
为了最小化撞击器对气溶胶的热转移导致的蒸发，建议对评估雾化溶液时冷却下一代撞击器（NGI）。这种方法增加了串行测试程序的测试时间。我们假设在初始长时间冷却后，可以在较短的再冷却时间后重复实验，而不会牺牲准确性。
使用连续输出（HUDSON）和呼吸增强（PARI LC Plus）雾化器（6 L/min）以 2.5 mg/3 mL 的沙丁胺醇溶液雾化至冷却至 4°C 的 NGI（内部和外部过滤器），校准至 15 L/min。比较了三种不同方案的质量中值空气动力学直径（MMAD）、几何标准偏差（GSD）、<5μm 的颗粒百分比（P%<5）和 1-3μm 的颗粒百分比（P%1-3）。所有方案（所有方案均为 90 分钟）均先进行初始冷却，然后再进行两次测量，再冷却间隔为 90 分钟和 90 分钟（方案 A）、60 分钟和 60 分钟（方案 B）或 30 分钟和 30 分钟（方案 C）。通过分光光度法（276nm）对沙丁胺醇进行稀释和测量。
所有方案（n = 9）的第一次测量的 MMAD、GSD、P%<5 和 P%1-3 为：3.47 ± 0.21 μm、2.31 ± 0.07、67.3 ± 2.6%和 40 ± 2.3%（PARI）和 4.56 ± 0.35 μm、2.16 ± 0.08、54 ± 3.7%和 22.4 ± 2.8%（HUDSON）。冷却方案之间无差异（p > 0.05）。从第一次测量的百分比变化范围为：-3.9 至 +2.1%（PARI）和-4.1 至 +2.9%（HUDSON）的 MMAD；-5.6 至 +2.6%（PARI）和-4.9 至 +1.9%（HUDSON）的 GSD；0 至 +4.6%（PARI）和-3.7%至 +5.7%（HUDSON）的 P%<5；和-2.4 至 +5.2%（PARI）和-1.8 至 +4.9%（HUDSON）的 P%1-3。
NGI 确定的雾化溶液的气溶胶特性不受在初始 90 分钟后再冷却 30 或 60 分钟后对撞击器进行两次重复测量的影响。
